Experimental and Numerical Analysis of Geotextile Encased and Ordinary Reclaimed Asphalt Pavement Infused Floating Granular Piles for Lean Clay Improvement

Abstract

This study investigates the use of Reclaimed Asphalt Pavement (RAP)-infused granular piles to enhance the load-bearing capacity and settlement performance of soft clay soils, increasingly utilized due to urbanization. Ordinary and Geotextile-Encased Floating Granular Piles (OGP and EGP) were evaluated through load-settlement tests across various RAP-to-stone aggregate ratios, with large-scale experiments and PLAXIS 3D simulations validating the results. The optimal mix of 50% stone and 50% RAP improved soil properties by balancing stiffness and flexibility, while geotextile encasement further enhanced performance by reducing lateral deformation and optimizing load transfer. Specifically, the geotextile-encased 50S-50R pile increased the ultimate bearing capacity by 29% compared to the 100% stone configuration. Although higher RAP content mixes were less effective due to lower stiffness, their performance improved significantly with geotextile encasement. The findings demonstrate that RAP-infused granular piles, especially when geotextile-encased, offer a viable and sustainable solution for soft soil improvement, promoting environmental and economic benefits in geotechnical engineering.

Keywords: Low-Plastic Clay, Granular Piles, Stone Column, Reclaimed Asphalt Pavement (RAP), Geotextile